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@@ -0,0 +1,473 @@
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+/*
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+ * Implementation of the Xen vTPM device frontend
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+ *
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+ * Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2,
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+ * as published by the Free Software Foundation.
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+ */
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+#include <linux/errno.h>
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+#include <linux/err.h>
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+#include <linux/interrupt.h>
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+#include <xen/events.h>
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+#include <xen/interface/io/tpmif.h>
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+#include <xen/grant_table.h>
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+#include <xen/xenbus.h>
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+#include <xen/page.h>
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+#include "tpm.h"
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+
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+struct tpm_private {
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+ struct tpm_chip *chip;
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+ struct xenbus_device *dev;
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+
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+ struct vtpm_shared_page *shr;
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+
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+ unsigned int evtchn;
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+ int ring_ref;
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+ domid_t backend_id;
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+};
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+
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+enum status_bits {
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+ VTPM_STATUS_RUNNING = 0x1,
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+ VTPM_STATUS_IDLE = 0x2,
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+ VTPM_STATUS_RESULT = 0x4,
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+ VTPM_STATUS_CANCELED = 0x8,
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+};
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+
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+static u8 vtpm_status(struct tpm_chip *chip)
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+{
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ switch (priv->shr->state) {
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+ case VTPM_STATE_IDLE:
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+ return VTPM_STATUS_IDLE | VTPM_STATUS_CANCELED;
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+ case VTPM_STATE_FINISH:
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+ return VTPM_STATUS_IDLE | VTPM_STATUS_RESULT;
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+ case VTPM_STATE_SUBMIT:
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+ case VTPM_STATE_CANCEL: /* cancel requested, not yet canceled */
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+ return VTPM_STATUS_RUNNING;
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+ default:
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+ return 0;
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+ }
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+}
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+
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+static bool vtpm_req_canceled(struct tpm_chip *chip, u8 status)
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+{
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+ return status & VTPM_STATUS_CANCELED;
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+}
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+
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+static void vtpm_cancel(struct tpm_chip *chip)
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+{
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ priv->shr->state = VTPM_STATE_CANCEL;
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+ wmb();
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+ notify_remote_via_evtchn(priv->evtchn);
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+}
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+
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+static unsigned int shr_data_offset(struct vtpm_shared_page *shr)
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+{
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+ return sizeof(*shr) + sizeof(u32) * shr->nr_extra_pages;
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+}
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+
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+static int vtpm_send(struct tpm_chip *chip, u8 *buf, size_t count)
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+{
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ struct vtpm_shared_page *shr = priv->shr;
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+ unsigned int offset = shr_data_offset(shr);
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+
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+ u32 ordinal;
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+ unsigned long duration;
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+
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+ if (offset > PAGE_SIZE)
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+ return -EINVAL;
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+
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+ if (offset + count > PAGE_SIZE)
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+ return -EINVAL;
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+
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+ /* Wait for completion of any existing command or cancellation */
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+ if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, chip->vendor.timeout_c,
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+ &chip->vendor.read_queue, true) < 0) {
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+ vtpm_cancel(chip);
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+ return -ETIME;
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+ }
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+
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+ memcpy(offset + (u8 *)shr, buf, count);
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+ shr->length = count;
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+ barrier();
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+ shr->state = VTPM_STATE_SUBMIT;
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+ wmb();
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+ notify_remote_via_evtchn(priv->evtchn);
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+
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+ ordinal = be32_to_cpu(((struct tpm_input_header*)buf)->ordinal);
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+ duration = tpm_calc_ordinal_duration(chip, ordinal);
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+
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+ if (wait_for_tpm_stat(chip, VTPM_STATUS_IDLE, duration,
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+ &chip->vendor.read_queue, true) < 0) {
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+ /* got a signal or timeout, try to cancel */
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+ vtpm_cancel(chip);
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+ return -ETIME;
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+ }
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+
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+ return count;
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+}
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+
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+static int vtpm_recv(struct tpm_chip *chip, u8 *buf, size_t count)
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+{
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ struct vtpm_shared_page *shr = priv->shr;
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+ unsigned int offset = shr_data_offset(shr);
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+ size_t length = shr->length;
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+
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+ if (shr->state == VTPM_STATE_IDLE)
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+ return -ECANCELED;
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+
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+ /* In theory the wait at the end of _send makes this one unnecessary */
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+ if (wait_for_tpm_stat(chip, VTPM_STATUS_RESULT, chip->vendor.timeout_c,
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+ &chip->vendor.read_queue, true) < 0) {
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+ vtpm_cancel(chip);
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+ return -ETIME;
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+ }
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+
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+ if (offset > PAGE_SIZE)
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+ return -EIO;
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+
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+ if (offset + length > PAGE_SIZE)
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+ length = PAGE_SIZE - offset;
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+
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+ if (length > count)
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+ length = count;
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+
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+ memcpy(buf, offset + (u8 *)shr, length);
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+
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+ return length;
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+}
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+
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+ssize_t tpm_show_locality(struct device *dev, struct device_attribute *attr,
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+ char *buf)
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+{
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+ struct tpm_chip *chip = dev_get_drvdata(dev);
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ u8 locality = priv->shr->locality;
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+
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+ return sprintf(buf, "%d\n", locality);
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+}
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+
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+ssize_t tpm_store_locality(struct device *dev, struct device_attribute *attr,
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+ const char *buf, size_t len)
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+{
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+ struct tpm_chip *chip = dev_get_drvdata(dev);
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ u8 val;
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+
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+ int rv = kstrtou8(buf, 0, &val);
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+ if (rv)
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+ return rv;
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+
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+ priv->shr->locality = val;
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+
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+ return len;
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+}
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+
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+static const struct file_operations vtpm_ops = {
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+ .owner = THIS_MODULE,
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+ .llseek = no_llseek,
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+ .open = tpm_open,
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+ .read = tpm_read,
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+ .write = tpm_write,
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+ .release = tpm_release,
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+};
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+
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+static DEVICE_ATTR(pubek, S_IRUGO, tpm_show_pubek, NULL);
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+static DEVICE_ATTR(pcrs, S_IRUGO, tpm_show_pcrs, NULL);
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+static DEVICE_ATTR(enabled, S_IRUGO, tpm_show_enabled, NULL);
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+static DEVICE_ATTR(active, S_IRUGO, tpm_show_active, NULL);
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+static DEVICE_ATTR(owned, S_IRUGO, tpm_show_owned, NULL);
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+static DEVICE_ATTR(temp_deactivated, S_IRUGO, tpm_show_temp_deactivated,
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+ NULL);
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+static DEVICE_ATTR(caps, S_IRUGO, tpm_show_caps, NULL);
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+static DEVICE_ATTR(cancel, S_IWUSR | S_IWGRP, NULL, tpm_store_cancel);
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+static DEVICE_ATTR(durations, S_IRUGO, tpm_show_durations, NULL);
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+static DEVICE_ATTR(timeouts, S_IRUGO, tpm_show_timeouts, NULL);
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+static DEVICE_ATTR(locality, S_IRUGO | S_IWUSR, tpm_show_locality,
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+ tpm_store_locality);
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+
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+static struct attribute *vtpm_attrs[] = {
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+ &dev_attr_pubek.attr,
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+ &dev_attr_pcrs.attr,
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+ &dev_attr_enabled.attr,
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+ &dev_attr_active.attr,
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+ &dev_attr_owned.attr,
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+ &dev_attr_temp_deactivated.attr,
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+ &dev_attr_caps.attr,
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+ &dev_attr_cancel.attr,
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+ &dev_attr_durations.attr,
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+ &dev_attr_timeouts.attr,
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+ &dev_attr_locality.attr,
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+ NULL,
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+};
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+
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+static struct attribute_group vtpm_attr_grp = {
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+ .attrs = vtpm_attrs,
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+};
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+
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+#define TPM_LONG_TIMEOUT (10 * 60 * HZ)
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+
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+static const struct tpm_vendor_specific tpm_vtpm = {
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+ .status = vtpm_status,
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+ .recv = vtpm_recv,
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+ .send = vtpm_send,
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+ .cancel = vtpm_cancel,
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+ .req_complete_mask = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
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+ .req_complete_val = VTPM_STATUS_IDLE | VTPM_STATUS_RESULT,
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+ .req_canceled = vtpm_req_canceled,
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+ .attr_group = &vtpm_attr_grp,
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+ .miscdev = {
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+ .fops = &vtpm_ops,
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+ },
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+ .duration = {
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+ TPM_LONG_TIMEOUT,
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+ TPM_LONG_TIMEOUT,
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+ TPM_LONG_TIMEOUT,
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+ },
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+};
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+
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+static irqreturn_t tpmif_interrupt(int dummy, void *dev_id)
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+{
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+ struct tpm_private *priv = dev_id;
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+
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+ switch (priv->shr->state) {
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+ case VTPM_STATE_IDLE:
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+ case VTPM_STATE_FINISH:
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+ wake_up_interruptible(&priv->chip->vendor.read_queue);
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+ break;
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+ case VTPM_STATE_SUBMIT:
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+ case VTPM_STATE_CANCEL:
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+ default:
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+ break;
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+ }
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+ return IRQ_HANDLED;
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+}
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+
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+static int setup_chip(struct device *dev, struct tpm_private *priv)
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+{
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+ struct tpm_chip *chip;
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+
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+ chip = tpm_register_hardware(dev, &tpm_vtpm);
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+ if (!chip)
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+ return -ENODEV;
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+
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+ init_waitqueue_head(&chip->vendor.read_queue);
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+
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+ priv->chip = chip;
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+ TPM_VPRIV(chip) = priv;
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+
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+ return 0;
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+}
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+
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+/* caller must clean up in case of errors */
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+static int setup_ring(struct xenbus_device *dev, struct tpm_private *priv)
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+{
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+ struct xenbus_transaction xbt;
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+ const char *message = NULL;
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+ int rv;
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+
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+ priv->shr = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
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+ if (!priv->shr) {
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+ xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
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+ return -ENOMEM;
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+ }
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+
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+ rv = xenbus_grant_ring(dev, virt_to_mfn(priv->shr));
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+ if (rv < 0)
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+ return rv;
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+
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+ priv->ring_ref = rv;
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+
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+ rv = xenbus_alloc_evtchn(dev, &priv->evtchn);
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+ if (rv)
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+ return rv;
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+
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+ rv = bind_evtchn_to_irqhandler(priv->evtchn, tpmif_interrupt, 0,
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+ "tpmif", priv);
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+ if (rv <= 0) {
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+ xenbus_dev_fatal(dev, rv, "allocating TPM irq");
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+ return rv;
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+ }
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+ priv->chip->vendor.irq = rv;
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+
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+ again:
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+ rv = xenbus_transaction_start(&xbt);
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+ if (rv) {
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+ xenbus_dev_fatal(dev, rv, "starting transaction");
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+ return rv;
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+ }
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+
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+ rv = xenbus_printf(xbt, dev->nodename,
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+ "ring-ref", "%u", priv->ring_ref);
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+ if (rv) {
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+ message = "writing ring-ref";
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+ goto abort_transaction;
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+ }
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+
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+ rv = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
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+ priv->evtchn);
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+ if (rv) {
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+ message = "writing event-channel";
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+ goto abort_transaction;
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+ }
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+
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+ rv = xenbus_printf(xbt, dev->nodename, "feature-protocol-v2", "1");
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+ if (rv) {
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+ message = "writing feature-protocol-v2";
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+ goto abort_transaction;
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+ }
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+
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+ rv = xenbus_transaction_end(xbt, 0);
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+ if (rv == -EAGAIN)
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+ goto again;
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+ if (rv) {
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+ xenbus_dev_fatal(dev, rv, "completing transaction");
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+ return rv;
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+ }
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+
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+ xenbus_switch_state(dev, XenbusStateInitialised);
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+
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+ return 0;
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+
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+ abort_transaction:
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+ xenbus_transaction_end(xbt, 1);
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+ if (message)
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+ xenbus_dev_error(dev, rv, "%s", message);
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+
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+ return rv;
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+}
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+
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+static void ring_free(struct tpm_private *priv)
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+{
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+ if (!priv)
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+ return;
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+
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+ if (priv->ring_ref)
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+ gnttab_end_foreign_access(priv->ring_ref, 0,
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+ (unsigned long)priv->shr);
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+ else
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+ free_page((unsigned long)priv->shr);
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+
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+ if (priv->chip && priv->chip->vendor.irq)
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+ unbind_from_irqhandler(priv->chip->vendor.irq, priv);
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+
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+ kfree(priv);
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+}
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+
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+static int tpmfront_probe(struct xenbus_device *dev,
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+ const struct xenbus_device_id *id)
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+{
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+ struct tpm_private *priv;
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+ int rv;
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+
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+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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+ if (!priv) {
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+ xenbus_dev_fatal(dev, -ENOMEM, "allocating priv structure");
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+ return -ENOMEM;
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+ }
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+
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+ rv = setup_chip(&dev->dev, priv);
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+ if (rv) {
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+ kfree(priv);
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+ return rv;
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+ }
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+
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+ rv = setup_ring(dev, priv);
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+ if (rv) {
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+ tpm_remove_hardware(&dev->dev);
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+ ring_free(priv);
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+ return rv;
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+ }
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+
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+ tpm_get_timeouts(priv->chip);
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+
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+ dev_set_drvdata(&dev->dev, priv->chip);
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+
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+ return rv;
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+}
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+
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+static int tpmfront_remove(struct xenbus_device *dev)
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+{
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+ struct tpm_chip *chip = dev_get_drvdata(&dev->dev);
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+ struct tpm_private *priv = TPM_VPRIV(chip);
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+ tpm_remove_hardware(&dev->dev);
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+ ring_free(priv);
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+ TPM_VPRIV(chip) = NULL;
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+ return 0;
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+}
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+
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+static int tpmfront_resume(struct xenbus_device *dev)
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+{
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+ /* A suspend/resume/migrate will interrupt a vTPM anyway */
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+ tpmfront_remove(dev);
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+ return tpmfront_probe(dev, NULL);
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+}
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+
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+static void backend_changed(struct xenbus_device *dev,
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+ enum xenbus_state backend_state)
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+{
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+ int val;
|
|
|
+
|
|
|
+ switch (backend_state) {
|
|
|
+ case XenbusStateInitialised:
|
|
|
+ case XenbusStateConnected:
|
|
|
+ if (dev->state == XenbusStateConnected)
|
|
|
+ break;
|
|
|
+
|
|
|
+ if (xenbus_scanf(XBT_NIL, dev->otherend,
|
|
|
+ "feature-protocol-v2", "%d", &val) < 0)
|
|
|
+ val = 0;
|
|
|
+ if (!val) {
|
|
|
+ xenbus_dev_fatal(dev, -EINVAL,
|
|
|
+ "vTPM protocol 2 required");
|
|
|
+ return;
|
|
|
+ }
|
|
|
+ xenbus_switch_state(dev, XenbusStateConnected);
|
|
|
+ break;
|
|
|
+
|
|
|
+ case XenbusStateClosing:
|
|
|
+ case XenbusStateClosed:
|
|
|
+ device_unregister(&dev->dev);
|
|
|
+ xenbus_frontend_closed(dev);
|
|
|
+ break;
|
|
|
+ default:
|
|
|
+ break;
|
|
|
+ }
|
|
|
+}
|
|
|
+
|
|
|
+static const struct xenbus_device_id tpmfront_ids[] = {
|
|
|
+ { "vtpm" },
|
|
|
+ { "" }
|
|
|
+};
|
|
|
+MODULE_ALIAS("xen:vtpm");
|
|
|
+
|
|
|
+static DEFINE_XENBUS_DRIVER(tpmfront, ,
|
|
|
+ .probe = tpmfront_probe,
|
|
|
+ .remove = tpmfront_remove,
|
|
|
+ .resume = tpmfront_resume,
|
|
|
+ .otherend_changed = backend_changed,
|
|
|
+ );
|
|
|
+
|
|
|
+static int __init xen_tpmfront_init(void)
|
|
|
+{
|
|
|
+ if (!xen_domain())
|
|
|
+ return -ENODEV;
|
|
|
+
|
|
|
+ return xenbus_register_frontend(&tpmfront_driver);
|
|
|
+}
|
|
|
+module_init(xen_tpmfront_init);
|
|
|
+
|
|
|
+static void __exit xen_tpmfront_exit(void)
|
|
|
+{
|
|
|
+ xenbus_unregister_driver(&tpmfront_driver);
|
|
|
+}
|
|
|
+module_exit(xen_tpmfront_exit);
|
|
|
+
|
|
|
+MODULE_AUTHOR("Daniel De Graaf <dgdegra@tycho.nsa.gov>");
|
|
|
+MODULE_DESCRIPTION("Xen vTPM Driver");
|
|
|
+MODULE_LICENSE("GPL");
|